The vital creepy-crawlies in our gardens
In the words of Antoine de Saint-Exupéry: “I must endure the presence of two or three caterpillars if I wish to become acquainted with the butterflies.”
Scientists believe that should we lose our insects we too could face extinction. It may sound dramatic, but crops would not be pollinated, leading to food shortages that would devastate the food chain. There are more than 24,000 insect species in the UK, and over a million in the world, and experts believe there are many more yet to be discovered. They represent more than half of all living organisms on the planet.
Closer to home you can see them at work. Although some insects can be pests – who loves a wasp in the summer? – many are beneficial and according to Dr Stephanie Bird, an entomologist based at RHS Wisley, they are crucial to the biodiversity of our gardens.
“Insects provide the basis for many functioning ecosystems,” explains Dr Bird. “They are an important source of food for birds, amphibians and mammals and play a vital role pollinating plants essential for growing vegetables and flowers. They also help to recycle plant waste – without insects being a part of the process, things wouldn’t decompose as efficiently.”
There are plenty of ways you can help them thrive. “Insects have different life stages; some have aquatic larvae so ponds are good,” Dr Bird says. “Put up bee houses for solitary bees, compost
heaps also provide a habitat for invertebrates and above all else provide a wide range of plants as food sources for caterpillars and flowers to provide nectar for pollinating insects including bees.’
Dr Bird stresses the need for urban greening – making sure urban areas don’t become concrete jungles with no plants. “Provide a variety of plants for the garden to flower across the year; different plants provide resources to different groups of insects. Pots can be great for small gardens, verbena, centranthus and buddleia attract butterflies, whilst bumblebees love lavender.” She advises trying a natural route such as netting to protect plants. “When you spray insecticides you can also be harming the insects that could be controlling the problem.”
Last year the RHS received the most calls about the box tree moth caterpillars. “A lot of people complain about ants in the pot plants, but sometimes they can provide control and eat the moth pupae,” she says.
And if you didn’t think we had enough insects already, the scientists at the RHS have just discovered another one, the webspinner – it’s the first insect order to be discovered in the UK for 100 years. May many more thrive in our gardens and beyond.
10 INTERESTING INSECTS THAT ARE GOOD FOR THE GARDEN
Ladybirds: These bright and easily identifiable beetles eat aphids.
Hoverflies: Larvae of some hoverfly species also eat aphids and the adult insects pollinate plants.
Bumblebees: Good pollinators.
Tachinid flies: Many species are parasitoids of caterpillars.
Lacewings: Again the larvae eat aphids and the adult insects look pretty interesting.
Glow worms: Actually a beetle, the larvae eat snails. The adult flightless females light up for a few weeks in the summer to attract a mate. Light pollution can interfere with this signalling behaviour, so if you know you live in an area where they are found then consider reducing artificial garden lighting between the end of June and mid-August.
Ground beetles: Both larvae and adults are predatory insects.
Parasitoid wasps:. These insects help control unwanted caterpillars.
Butterflies: Dr Bird says: “Some caterpillars like those of the common butterfly do eat garden plants; however, the adults are so attractive that in my opinion they are well worth the feeding damage.”
Hornet: The European hornet is a native, useful predatory insect that can help reduce pest populations in gardens – although its sting should be avoided!
With many pollinating insects in decline the RHS has produced a list of what plants to add to your garden. You can find out more at rhs.org.uk
‘Insects provide the basis for many functioning ecosystems’
Verbena bonariensis with hoverfly on Plants for Bugs research beds at RHS Wisley Gardens